In many connections there is a desire to fasten an object to a frame, which can be of such a kind that the locations of the fastening points are not decided beforehand. There is also often a desire to be able to fasten the object either along its long sides of its short sides or along all four side edges of the object and preferably without using tools.
If the object is for example a solar collector cassette which is to be mounted to a slanting roof, it is required that the cassette should be easily mountable and dismountable without making any infringement in the cassette, which in some cases can consist of a water reservoir.